Piston for internal-combustion engines.



K. I. E. HESSELIVIAN.

PISTON FOR INTERNAL COMBUSTION ENGINES. APPLICATION FILED JUNE I6, I915.

Patented Apr. 25, 1916.

Iii

PISTON FOR INTERNAL-COMBUSTION ENGINES.

Linnea.

Application filed June 16, 1915.

To all whom it may concern Be it known that I, KNUT JONAS ELIAS l'dnssELMAN, a citizen of the Kingdom of Sweden, residing at Saltsjo- Storangen, Stockholm, Sweden, have invented new and useful Improvements in Pistons for Internal-Combustion Engines, of which the following is a specification.

In two stroke internal combustion engines in which the work is in part regulated by that the piston uncovers ports in the wall of the cylinder, serving to exhaust the products of combustion and eventually also to admit scavenging air, the piston must be of such length, that it covers said ports even'in its uppermost or innermost position, and moreover, the piston has to fit rather tightly in the cylinder. If such a piston be combined with a cross-head, the cylinder and the guide of the crosshead have to be exactly parallel, owing to the accurate fitting of the piston in the cylinder. Besides, the piston andthe crosshead are to be so assembled, that the piston is concentric and exactly parallel with the cylinder. As is evident, this adjustment and parallelism may easily be disturbed by the wear of the crosshead, and said wear can not exceed certain narrow limits without causing bending strains 'between the cylinder and the piston, which strains may easily become detrimental to both of them. This inconvenience is obviated by the present invention which consists in this that the piston is composed of two portions viz. an upper (inner) tightening portion taking up the cylinder pressureand rigidly secured to the piston rod and the crosshead, and a lower (outer) portion connected to the upper portion of the piston or to the piston rod and the crosshead in such manner, that said lower portion partakes in the movement of the said movable members in the longitudinal direction of the cylinder, but is capable of moving or swinging laterally in relation to said, members.

In the accompanying drawing Figures 1, 2 and 3 show each in sectional view one constructional form of the invention. Fig. 4 shows a fourth form thereof. Fig. is a cross-section on line AB of Fig. 4 viewed in the direction of the arrows, and Fig. 6 shows a fifth form of-the invention.

In all the constructional forms shown in the drawing the piston is composed of an upper tightening portion 1 rigidly secured to the piston rod 2 and the crosshead 3 re Specification of Letters Patent.

Patented AIM. 25, rain.

Serial No. 34,470.

spectively, and of a lower portion 4 fitting tightly in the cylinder and serving in the different positions ofthe portion 1, except the lowermost position, to cover the port or ports 5 in the wall of the cylinder, through which the products of combustion are exhausted and the scavenging air eventually is admitted. The connection mentioned above between the lower portion 4 and the upper portion 1 of the piston or between the piston rod and the crosshead may be effected in different manners, and hence the devices illustrated in the drawing are only shown by way of example.

According to Fig. 1 the portion 4 of the piston is at the bottom connected to the piston rod by means of links 6 (one of which only is shown in the drawing) causing said portion to partake in the longitudinal movements of the piston rod, but allowing at the same time said members to move laterally in relation to each other. This possibility of moving laterally liberates the portion 4 from the strains otherwise arising from the wear of the crosshead, Of course, in pistons made in one piece and rigidly secured to the piston rod and the crosshead, it is the lower end of the piston that, on the wear of the crosshead, will be exposed to the greatest strains, and on account thereof, it is necessary in the present invention to take care of, in the first place, that the lateral movement of the piston rod and the cross-head in-relation to the lower portion of the piston can take place at the lower end of the latter.

According to the constructional form shown in Fig. 2 there are secured to the piston rod 2 two collars 7 formed in conformity with spherical surfaces and grasping the edge of the aperture in the bottom 8 of the portion 4, through which the piston rod is passed. The bottom 8 is likewise formed according to a spherical surface, and the aperture in the bottom has such a width. that the piston rod may to a certain extent move laterally in relation to the portion 4, which by the collars 7 is caused to partake in the longitudinal movements of the piston rod. i

In Fig. 3 a lengthwise movable collar 9 is placed on the piston rod 2 and is kept pressed by a spring 10 against the bottom 8 of the portion 4. The collar 9 as well as the bottom 8 may, preferably, also in this case. be of spherical form. At the top the portion 4 bears by means of a flange 11 against a corresponding surface of the portion 1 of the piston.

In the constructional form shown in Figs. 4 and 5 spring rods 11 are secured to the portion 1 of the piston and passed through corresponding apertures in the bottom -of the portion 4 to which the said rods are fastened by means of nuts 12 or the like.

The constructionalform shown in Fig. 6 differs from that shown in Figs. 4 and 5 in this only that the rods 11 are at the top fulcrumed to the portion 1 of the piston.

Having now described my invention what I claim as new and desire to secure by Letters Patent is: s

1. In aninternal combustion engine, the combination of a cylinder, ports'in the wall of said cylinder, a piston rod, a piston divided in an inner and an outer portion, the inner portion being rigidly secured to said piston rod and arranged to take up the cylinder pressure, and the outer portion being movably connected to said inner portion and arranged to close said ports, substantially as and for the purpose set forth.

2. In an internal combustion engine, the combination of a cylinder, ports in the wall of said cylinder, a piston rod, a piston divided in an inner portion rigidly secured to said piston rod and arranged to take up the cylinder pressure, and an outer portion connected to said inner portion and movable laterally in relation to said piston rod, said outer portion being arranged to close said ports, substantially as and for the purpose set forth.

3. In an internal combustion engine, the combination of a cylinder, ports in the wall of said cylinder, a piston rod, a crosshead rigidly secured to the said piston rod, a piston divided in an inner tightening portion rigidly secured to the piston rod and arranged to take up the cylinder pressure, and an outer portion connected to said inner portion and movable laterally in relation to the piston rod and the cross-head, said outer portion partaking in the movements of the piston rod and the crosshead and arranged to close the said ports, substantially as and for the purpose set forth.

In testimony whereof I have signed my name in presence of two subscribing witnesses.

KNUT JONAS ELIAS HESSELMAN.

Witnesses: 1

EVALD DELMAR, J OHN DELMAR. 

